Power conversion machine having pistons which are moved in a turning movement in a spherical housing

ABSTRACT

A power conversion machine which is provided with a spherical housing (10) with piston construction (36,37) having two-double-acting pistons (36) turnable about a first axis (x--x) cooperating with a partition plate (40) tiltable about a second axis (z--z) for defining four work chambers with piston surfaces (36a, 36b) going forwards and backwards. The partition plate is connected forcibly to the piston construction so that the partition plate is subjected to a tilting movement while the piston construction is subjected to turning, without thereby turning the partition plate. Inlet openings and outlet openings which are placed one after the other in communication with the four work chambers, are opened and closed by a control effected by joint movement of the pistons and the partition plate.

The present invention relates to a power conversion machine having apair of mutually opposite, separately double-acting pistons which aremoved in a turning motion in a spherical housing, where the pistons arerigidly connected to each other via a common hub portion centrally inthe spherical housing and are disposed each on its respective side of acentrally arranged, transversely extending partition plate which islocally passed through by the hub portion of the pistons and where thepistons at diametrically opposite ends, that is to say asymmetricallyrelative to each piston, are pivotably mounted each via its respectiverotary pin in the spherical housing about a first axis.

From U.S. Pat. No. 4,441,869, a power conversion machine of theafore-mentioned kind is known. Two mutually coherent, oppositelydirected, conic stump-shaped pistons are proposed which are rolled offon opposite sides of a common, stationary partition plate in thespherical housing. More specifically, pairs of alternately volumeincreasing and volume reducing work chambers are defined by means ofeach piston and a slide plate (hub portion) between the pistons, onopposite sides of the roller structure between the piston and thepartition plate. Here one is dependent upon a slide plate which connectsthe pistons to each other and which is tiltable in a sealed-off slot inthe stationary partition plate.

With the present invention the aim is a simpler and, in practice, morereadily adaptable solution from a constructional and utilitarianviewpoint. In particular, the aim is a solution where one avoids thementioned rolling off movements of the pistons against the partitionplate and the axial sliding movement of the slide plate which connectsthe pistons to each other, and where one can, instead, employ a morereadily controllable to-and-fro movement of the pistons andsimultaneously a connection more readily sealable between the pistonsand the partition plate.

The power conversion machine according to the invention is characterisedin that each piston in a manner known per se has the form of a sphericalsegment with oppositely directed piston surfaces which outermost areterminated by the spherical surface of the spherical segment or thepiston and which innermost are connected to each other via said hubportion with intermediate part-cylindrical hub portion surfaces whichform bearing surfaces against equivalent part-cylindrical partition wallsurfaces, and that the partition plate is pivotably mounted in thespherical housing about another axis which crosses the first axis in thecentre of the spherical housing, the partition plate at opposite ends ofthe hub portion of the pistons being provided with bearing portions witha part-cylindrical bearing surface for each piston and with end bearingsurfaces corresponding to end bearing surfaces in the hub portion of thepistons.

From United Kingdom Patent Specification Nos. 1,259,801 and 1,549,269solutions are known where each piston has the form of a sphericalsegment with oppositely directed piston surfaces which are terminatedoutermost by the spherical surface of the spherical segment or thepiston. The pistons define directly between them two oppositely actingwork chambers.

By employing according to the invention a pivotably mounted partitionplate one can obtain purely constructionally a simpler and moreeffective cooperating connection between the partition plate and thepistons. In particular the partition plate can be allowed to participatein certain movements together with the pistons and in other movementsrelative to the pistons, so that the change in volume can be achieved inthe respective work chambers by a compound, forcibly controlled,relative movement of the pistons and the partition plate. Morespecifically the piston surface and the opposite surface of thepartition plate can be tilted towards and away from each other, at thesame time as the pistons and the partition surface move collectively ina mutually forcibly controlled manner relative to the inner surface ofthe spherical housing.

By employing according to the invention pistons in the form of sphericalsegments and a partition plate which is tiltably connected to thepistons, it can be made possible that the piston surfaces andequivalent, opposite surfaces in the partition plate are designed withvarying form as required, in order to suit the compression conditions,opening and closing of inlet and outlet openings, possible valveopenings, etc. in a manner most favourably possible according to theconditions. For example the said surfaces can be planar or haveequivalent, more or less arbitrary curved contours by locally increasingor decreasing the thickness of the partition plate and the pistons.

According to the invention it will also be possible to set the size ofthe work chambers, all according to the dimensions which are establishedfor the partition plate and the pistons and according to which anglesare established between the rotary axis (said first axis) of the pistonpins and the tilting axis (the hub axis) of the pistons.

According to the invention by means of the two pistons and theco-operating partition plate, over an angle of rotation of 360°, foreach of the four work chambers, two successive work cycles can beachieved each with its respective suction and exhaust step (for examplefor two-stroke combustion engine) and a work cycle, respectively, withcorresponding four work steps (four-stroke combustion engine). With anangle between the afore-mentioned axes of for example 35° one can get ineach of the four work chambers of the machine a collective (to-and-fro)angular movement for each piston of 140° (4°×35°) and thereby a totalangular movement for all four pistons of 560°. It is a substantialadvantage for certain use examples according to the invention that eachwork cycle can be established for a 180° angle of rotation, of whichalmost one half of the angle of rotation (close to 90°) is employed forthe inlet step, while almost the other half of the angle of rotation(close to 90°) is employed for the outlet step. Correspondingly, it isan advantage for other fields of use (for example for a four-strokecombustion engine) that each work cycle (four strokes I-IV) can beestablished for a 360° angle of rotation, of which almost one half ofthe angle of rotation can be employed for two of the strokes (forexample the strokes I and II), while almost the other half of the angleof rotation can be employed for the other two ones of the strokes (forexample, the strokes III and IV). Further it is in the last-mentionedcase an advantage that two neigbour chambers one by one run through twosuccessive work strokes. By the use of two motor units on one and thesame axis one can let associated work chambers one by one run throughall four work strokes (I-IV).

According to the invention one can in this way (in two-stroke combustionmotor or in other motor or machine) achieve an effective control of theinlet step in two of the work chambers, while at the same time one has acorrespondingly effective control of the outlet step in the tworemaining work chambers. After a work cycle of 180° (rotating 180° inthe spherical housing) with mutually successive inlet and outlet stepsincluded therein, an equivalent further work cycle of 180° is achievedwith corresponding inlet and outlet steps. If desired the angle betweenthe said two axes can be set at a higher or lower angle than the saidangle of 35°, in order thereby to alter the volume in each work chambercorrespondingly for each work step.

Purely constructionally, it is preferred that the pistons and theircommon hub portion are passed through by a crank shaft which via a thirdaxis of rotation is turnably mounted in the pistons and which has rotaryand thrust bearings in each piston, the crank shaft being rigidlyconnected in a manner known per se to the said rotary pins.

In this way mounting of the pistons can be achieved in an effectivemanner with the associated hub portion on a common crank shaft passingthrough with the possibility for an effective through flow of lubricantin the bearing portions between crank shaft and the pistons.Simultaneously an effective sealing between the lubricant passage andthe respective work chambers in the spherical housing can be ensured ina ready manner.

It is an essential advantage according to the invention that the pistonswith associated common crank shaft together form a rigid body ofrotation which is pivotable inside the spherical motor housing chamber,that is to say pivotable between two shaft journals which are pivotablymounted in the motor housing just outside the motor housing chamber. Itis a corresponding advantage that the partition wall, which also is inthe form of a rotation body, is tiltable in said motor housing chamberand is pivotably mounted in the motor housing just outside the motorhousing chamber in the hollow space which is formed between the pistonsand the crank shaft. One has the possibility to forcibly control thetilting movement of the partition wall in a an accurate and controlledmanner within the rotary movement of the pistons, so that retardationforces are avoided both in the pistons and in the partition wall. Onehas also the possibility to form said members in a specially compactmanner, with little need of space, that is to say with large volumetricefficiency. Further one has the possibility to achieve minimal frictionwith minimal fit tolerance and with an accurate adaptation of themembers in relation to each other.

By having according to the invention a work cycle of 180° (against 270°by the solution according to Norwegian Patent Specification No. 81 0691)it is achieved a far simpler arrangement, with a simpler and moreadvantageous location of inlet and outlet openings and possibly otherequipment, with a smaller number of valves or possibly without valvesand with a simpler and more effective control of valves and otherequipment. In addition it can be achieved relatively simple sealingwhere this is necessary.

The machine according to the invention can owing to the relatively highefficiency with a relatively small volume and thereby with little needof space be used for many different purposes of employment. For example,the machine can be used in the form of a compressor, pump, pneumatic orhydraulic motor, piston steam engine, Stirling motor, or the like Insuch a case the inlet openings and the outlet openings, respectively,can be controlled by the movements of the pistons and the partitionplate, respectively, in relation to the spherical housing, without theuse of valves or other control arrangements.

In case the machine is in the form of a four-stroke combustion engine,the exhaust openings and the scavenge air openings can be controlledpartly by separate valves and partly by the partition plate and thepistons, respectively, by covering and uncovering, respectively, of theopenings with the partition plate and the pistons, respectively. One canin this way in certain of the strokes control, that is to say keep openand keep closed, respectively, the exhaust openings and the scavenge airopenings with valves, while the time and duration of the air scavengingand the exhaust emptying in its entirety can be controlled by themovements of the partition plate and the pistons, respectively.

In case the machine is in the form of a Stirling motor, the machine canconsist of two motor units which each is connected to its end of acommon shaft, the one motor unit being joined with a heating device,whereas the other motor unit being joined with a cooling device, and aheat exchanger being arranged about the common shaft between the coolingdevice and the heating device. It is thus in several ways achieved aspecially favourable solution with the possibility of a tightlycontracted motor with volumetric high efficiency. This causes that themachine, that is to say the Stirling motor, can have great employment ina series of different fields.

It is in the last-mentioned case preferred that the two motor units areconnected with each other via an angle regulating device, for regulationof the working step of the motor units in relation to each other, theregulating device being preferably in the form of a pivot piston devicewhich is controlled and hydraulically operated by a regulating valve,and that the regulating device is adjusted, by angle rotation of themotor units in relation to each other about a common rotating axis, tocontrol the motor power and to rotate the pair of motor units foroperation in two mutually opposite pivot directions, respectively.

Further features of the invention will be evident from the followingdescription having regard to the accompanying drawings, in which:

FIG. 1 shows a vertical section of the machine according to theinvention, illustrated in the form of a compressor, with the pistonsillustrated in the one outer position and with the section madecentrally through the common crank shaft of the pistons.

FIG. 2 shows partially in section and partially in side view the machineaccording to FIG. 1, with the same piston position as shown in FIG. 1,but illustrated in a section at right angles to the section in FIG. 1.

FIG. 3 shows the machine partially in section and partially in side viewsimilarly as in FIG. 2 after a 45° turn of the crank shaft out of theposition illustrated in FIG. 2.

FIG. 4 shows a section made centrally through the common crank shaft ofthe pistons with the pistons shown in the same angular position asillustrated in FIG. 3.

FIG. 5 shows schematically a machine according to the invention, in theform of a triple-expansion piston steam engine, where also the feed pumpof the steam engine is made of a machine according to the invention.

FIG. 6 shows a detail of the machines according to FIG. 5, illustratedin section.

FIG. 7 shows schematically a machine according to the invention, in theform of an eight-chamber Sterling motor.

FIGS. 8 and 9 show a regulating device for the Stirling motor accordingto FIG. 7, shown by section 8--8 in FIG. 9 and by section 9--9 in FIG.8, respectively.

FIGS. 10 and 11 show a machine according to the invention, in the formof a four-stroke combustion engine.

FIG. 12 shows schematically the four strokes for respective four motorchambers in the machine according to FIGS. 10 and 11.

FIG. 13 illustrates a piston construction in accordance with theinvention;

FIG. 14 illustrates a further view of the piston construction inaccordance with the invention; and

FIG. 15 illustrates a perspective view of a partition plate constructedin accordance with the invention.

In the drawings FIGS. 1-4 there is shown a power conversion machinewhich in the present embodiment example is illustrated in the form of acompressor for pumping gaseous pump medium and in the form of a pump forpumping liquid pump medium, respectively. Alternatively, the machine canbe used as pneumatic or hydraulic motor driven by gaseous or liquidpressure medium, respectively.

A spherical housing 10 is illustrated which is made up of two in themain similar components 10a and 10b. The components 10a, 10b are jointedtogether via equivalent flange portions 11 with fastening holes 11a andassociated fastening bolts 12, so that a spherical space 13 is definedinternally in the housing.

Each housing component 10a and 10b is provided with a sleeve-shapedbearing portion 14 at the end opposite the flange portion 11. In thebearing portion 14 there is shown in FIG. 1 a pair of combined rotaryand thrust bearings 15, 16 in which there are rotatably mounted a rotarypin 17a and 17b, which form a part of a crank shaft 18. The crank shaft18 passes through the housing 10 with associated bearing portions 14.The main portion 18a of the crank shaft 18 is securely connected to therotary pins 17a and 17b. In the illustrated embodiment the rotary pinsand the main portion 18a of the crank shaft 18 are of unitaryconstruction. In the transition between the rotary pin and the mainportion 18a of the crank shaft there is a collar portion 19 which formsa seal against the bearing portion 14 via a gasket 20. The main portion18a of the crank shaft 18 is provided with a central, cylindrical stemportion 21 having a minimum diameter d1 and a pair of opposite hubportions 22 with medium diameters d2 and a further pair of oppositespherical shell portions 23 having the maximum diameter d3.

The crank shaft 18 is turnably mounted about a first rotary axis x--xthrough the center of the rotary pins 17a, 17b and the center of thehousing 10, while the main portion 18b of the crank shaft has a mainaxis y--y which in the illustrated embodiment forms an angle of 35° withthe axis x--x. The main portion 18a of the crank shaft is turnablymounted in a piston construction 24 having an internal sectionallygraduated bore 25 which receives the main portion 18a with a certain fitand with intermediate bushes 26, 27. At 28 and 29, seals are shownbetween the respective spherical shell portion 23 and the pistonconstruction 24 and at 30 and 31 seals are shown between the sphericalend surface 32 of the piston construction 24 and the internal sphericalsurface 33 of the housing 10 and the spherical inner surface 34 of thehub portion 22, respectively. There is shown a through passage 35 viathe rotary pin 17a, the hub portion 22, the spherical shell portion 23and the annular intermediate space between the main portion 18a of thecrank shaft and the bore 25 in the piston construction together with thespherical shell portion, the hub portion and the rotary pin 17a at theopposite end of the crank shaft.

The piston construction 24 consists of two opposite pistons 36 togetherwith an intermediate, common hub portion 37, which constitute a coherentunit. More specifically the piston construction 24 is fabricated in twohalf components (divided along the axis y--y and at right angles to theplane of the drawing in FIG. 1) which are fastened together with screwbolts or similar releasable fastening means in a manner not shownfurther. By this the piston construction can be mounted in positionoutside the crank shaft in a ready manner

Each piston 36 is provided with two opposite piston surfaces 36a, 36bwhich are shown in the drawing in the form of planar surfaces at rightangles to the plane of the drawing in FIG. 1. The intermediate hubportion 37 is provided with equivalent mutually opposite cylindricalsealing surfaces 37a and 37b. The hub portion 37 has a shorter dimensionacross the plane of the drawing in FIG. 1 than the pistons 36 and isprovided at the ends with radial sealing surfaces which thrust axiallyagainst equivalent radial sealing surfaces in opposite hub portions 38and 39 in a partition plate 40 (see FIG. 2). From FIG. 1 it is evidentthat the hub portion of the piston construction is arranged in a throughslot in the partition plate 40 with seal-forming abutment via sealingsurfaces 37a and 37b against concave sealing surfaces 41a, 41b in theslot which is cut out centrally in the partition plate 40.

Referring to FIGS. 13 and 14, the pistons 36a, 36b and hub 37 aredivided in two halves along a partition line A. This allows mounting ofthe crank shaft therein.

Referring to FIG. 15, the partition plate 40 is also divided along apartition line B to allow for mounting of the pistons/hub membercentrally in the partition plate 40.

As indicated, the pistons/hub member 36, 37 are arranged to be clampedcentrally of the partition plate 40 in a gap (see FIG. 15) provided inthe partition plate 40. The hub portion 37 is allowed to perform arocking movement in the gap between concave sealing surfaces 41a, 41band between the hub portions 38, 39 of the partition plate 40.Accordingly, the plate 40 is allowed to participate in part of therocking or pivoting movement of the piston hub member 36, 37, and thusrock about the axis Z--Z.

The only connection that is provided between the partition plate 40 andthe piston/hub member is the clamping provided between the hub portions38, 39 and the hub portion 37 and between the sealing surfaces 41a, 41band the hub portion 37. As indicated in FIG. 1, the partition plate 40is pivoted about the axis Z--Z via the pivot pins 42, 43.

By pivoting on the axis X--X, the pistons/hub member 36, 37 causes arocking movement of the piston/hub member 36, 37 about the axis Y--Y ofthe crank shaft member 18. This rocking movement of the piston/hubmember 36, 37 is controlled by the partition plate 40. Morespecifically, part of the rocking movement of the piston/hub member isallowed to take place by allowing the partition plate 40 to rock aboutthe axis Z--Z. The remaining rocking movement of the pistons/hub memberis provided by the rotation of the crank shaft member 18 in thepistons/hub member 36, 37.

The partition plate 40 is provided at its peripheral edge with twoopposite pivot pins 42, 43 which are pivotably mounted in associatedbearing sleeves 44, 45 in corresponding cavities in the flange portionsmutually thrust together about an axis z--z. The partition plate isprovided with two opposite disc portions 46, 47 in the form of sphericalsegments which are connected to each other via the said hub portions 38,39 (see FIG. 2). For reasons of assembly the partition plate 40 isdivided into two parts parallel to the plane of the drawing in FIG. 1(see FIG. 15).

In FIG. 1 the pistons 36 are shown in their respective one outerposition where a work chamber 48a and 49a is formed having a maximumvolume on opposite sides of the partition plate 40 between the pistonsurface 36b and the partition plate surface 47a and 46b. Similarly thereis formed a work chamber (48b and 49b as shown further in FIG. 3) havinga minimum volume on opposite sides of the partition plate 40 between thepiston surface 36a and the partition plate surface 47b and 46a.

In FIG. 2 there is indicated by broken lines 50a the one of two inletopenings (which are arranged mutually diametrically opposite) in thespherical inner surface of the housing 10 just by the joint between thetwo housing components 10a and 10b. Similarly there is indicated bybroken lines 50b the one of two outlet openings which are arranged inthe spherical inner surface of the housing 10 just by the joint betweenthe two housing components 10a and 10b. In FIG. 2 there is indicated theone inlet opening 50a and the one outlet opening 50b each arranged onits respective side of the pivot pin 42 of the partition plate 40, inthe one portion of the housing 10 which is omitted in FIG. 2, whileequivalent openings 50b and 50a are arranged in a similar manner each onits respective side of the other pivot pin 43 in the rear wall of thehousing 10 in FIG. 2. In the position illustrated in FIG. 2 fouropenings combined are covered by the spherical end surfaces 46c (47c) ofthe partition plate 40. On swinging the partition plate 40 outwards fromthe position shown in FIG. 2--caused by a turning in the direction ofrotation as illustrated by an arrow P1 of the crank shaft 18 withassociated pistons 36 and hub portion 37 about the axis x--x and acorresponding tilting in the direction of tilt as shown by an arrow P2of the partition plate 40 about its axis z--z--each of the openings 50aand 50b will be placed in communication with their respective workchambers 48a, 48b, 49a, 49b.

In FIG. 3, the pistons 36 and the partition plate 40 are shown in anintermediate position between two outer positions, that is to say afterturning of the pistons 36 90° about the axis x--x and a correspondingforcible retilting of the partition plate 40 35° about the axis z--z. Inthe intermediate position shown in FIG. 3 there is indicated an exposedarea 51 and 52 (as indicated by cross-hatching) between the sphericalend surface 47c (46c) of the partition plate 40 and the spherical endsurface 36c of the respective piston 36. It will be evident from FIG. 3that the areas 51 and 52 will be controlled by the movement of thepartition plate 40 and the respective piston 36 jointly. From theposition shown in FIG. 2 to the position shown in FIG. 3 the workchamber 48a (49a) will decline in volume while the work chamber 48b(49b) will increase in volume.

From that in FIG. 3 to the other outer position of the pistons thepartition plate 40 will tilt back towards the starting position of thepartition plate as shown in FIG. 2, by tilting in the direction of tiltas shown by an arrow P3. By this reverse tilting of the partition platethe work chamber 48a (49a) will continue to decline in volume towards aminimum (similarly as indicated in FIG. 2 for the work chamber 48b),while correspondingly the work chamber 48b (49b) will continue toincrease in volume towards a maximum, after turning of the pistonconstruction 180° from the starting position as shown in FIG. 1 and 2.Thereafter the chamber 48a (49a) will increase in volume in a newequivalent cycle while the chamber 48b (49b) correspondingly declines involume while the piston construction passes through the final 180° of aturn of 360° back to the starting position in FIG. 1 and 2. During this360° turn each work chamber 48a, 48b, 49a, 49b has undertaken a fullyclosed work cycle with inlet and outlet (or outlet and inlet) of workingmedium, that is to say four equivalent volumes in pairs one after theother. In FIG. 4 there are shown two pipe stubs 53 and 54, each of whichcommunicates with their respective associated inlet opening and outletopening in the housing 10 in a manner not shown further via the wallportion at the flange portions 11 of the housing components 10a, 10b.Two further pipe stubs are similarly arranged on diametrically oppositewall portions of the housing connected to the two remaining openings(the inlet opening and the outlet opening).

In the illustrated embodiment in FIGS. 1-4 the invention is shown in theform of a compressor or pump for pumping gaseous or liquid workingmedium. However, the construction can as mentioned be used just as wellin the form of a pneumatic or hydraulic motor which is driven by agaseous or liquid working medium (pressure medium). In the following itshall as illustrating embodiments be described a variety of differentmachine types with associated additional equipment, but with maincomponents corresponding to the main components according to theembodiment in FIGS. 1-4.

A second embodiment as shown in FIG. 5 illustrates a triple-expansionpiston steam engine 60 with three steam motors 61, 62, 63 connected inseries. The motor 61 is fed with live steam from a steam boiler 64 viatwo parallel steam feed pipes 64a, 64b, while exhaust steam from themotor 61 is fed to the motor 62 via two parallel steam pipes 65a, 65band exhaust steam from the motor 62 is fed via two steam pipes 66a, 66bto the motor 63 and exhaust steam from the motor 63 via two pipes 67a,67b is fed to a steam condenser 68. From the condenser 68 is fedcondensate via a pipe 68a to a cascade tank 69. From the cascade tank 69a pipe 70 passes which branches off in two branch pipes 70, 70b to afour-chamber feed pump 71. From the feed pump 71 two branch pipes 72a,72b pass to the steam boiler 64.

Each of the motors 61, 62, 63 and the feed pump 71 is of correspondinggeneral construction as shown in FIG. 6 and in FIG. 1-4, respectively.

In FIG. 6 it is shown the one section 10a of a two-piece housing 10. Thepartition is corresponding to that described in connection with theconstruction in FIGS. 1-4. In the housing it is shown a pair of mutuallydiametrically opposite inlet openings 50a and an equivalent pair ofintermediate, mutually diametrically opposite outlet openings 50b whichare opened and closed, without the use of extra valves, controlled bythe movement of a partition plate 40 corresponding to the partitionplate in FIGS. 1-4 and controlled by pistons 36 corresponding to thepistons in FIGS. 1-4, respectively, in relation to the interior surfacesof the housing sections. The partition plate 40 is mounted tiltablyabout pivot pins 42, 43 in the housing 10 in a corresponding manner asshown for the pivot pins in FIGS. 1-4. The construction and the mode ofoperation for the partition plate 40 and the pistons 36 arecorresponding to what is described for the partition plate 40 and thepistons 36 according to FIGS. 1-4.

In FIG. 7 the machine according to the invention is shown in the form ofa eight-chamber Stirling motor or engine with a closed, regenerativecircuit with heat recovery, where the work medium is compressed andexpanded at different temperature levels. The Stirling motor or enginecan be constructed as motor, heat pump, pressure generator and coolingengine, respectively, or the like, as required. In the illustratedembodiment the Stirling motor is intended used as motor, with externalcombustion or other external heating and with equivalent externalcooling.

It is shown a schematic arrangement of two motor units 85, 86, connectedin series, connected to a common drive shaft via bearings 88, 89a, 89b,90. The one motor unit 85 is surrounded by a cooling device 91 (theperiphery indicated in fully drawn lines) and the other motor unit iscorrespondingly surrounded by a heating device 92 (the peripheryindicated in fully drawn lines). A shaft connection 93 (indicated inbroken lines) between the motor units 85, 86 and the associated bearings89a, 89b is surrounded by a heat exchanger or ordinary regenerator 94(the periphery indicated in fully drawn lines).

By the solution according to the present invention it is so arrangedthat the one, cooled motor unit 85 has four separate chambers, of whichonly two chambers 85a, 85b are illustrated in FIG. 7, while the othermotor unit 86 has equivalent four separate chambers 86a, 86b, 86c, 86d.It is shown four separate guide passages 95a, 95b, 95c, 95d between thetwo motor units 85, 86. More precisely, each of the four chambers in theone motor unit is connected with their respective chamber in the othermotor unit via their respective said passages. In this way it isachieved an arrangement with two pairs of double acting pistons, that isto say two double acting pistons in each motor unit. The pistons in theone motor unit is 90° phase-displaced in relation to the pistons in theother motor unit. This causes that the pistons of the two motor units incertain parts of the work cycle compress the medium between them whilethey in certain other parts of the work cycle let the medium expandbetween them and in further parts of the work cycle allow transmissionof the medium from work chamber to work chamber. (Ordinary Stirlingcycle to a system of two parts of double acting pistons).

It is not shown the details of the cooling device 91 or of the heatingdevice 92 and the heat exchanger, respectively, as FIG. 7 illustratesthe solution as a principle sketch, without laying special emphasis onthe details. For example, the passages can be made substantiallydifferent from what is shown in the drawings, with regard to lengthextension as well as to general course, as will easily be evident to theskilled man. However, it is a demand that the pipes have mutually thesame length and mutually the same volume.

With arrows P2 it is shown the one of the two opposite tiltingdirections for the partition wall 40 in the two motor units and witharrows P1 it is shown the pivot direction for the piston constructionwith the two pistons 36. The pistons 36 in the one motor unit 86 areshown in the one external position, while the pistons 36 in the othermotor unit 85 take an intermediate position. The piston arrangements ofthe two motor units are in FIG. 7 shown angularly displaced 90° inrelation to each other relative to the rotation axis, so that the workchambers of the one motor unit the whole time are lying 90°phase-displaced in relation to the work chambers in the other motorunit.

An essential part of the solution according to the invention is that itis used two motor units, which individually both in construction and inmode of operation mainly correspond to the solution as shown in FIGS.1-4. However, it must be remarked that in the solution according to theinvention, with regard to the Stirling motor, it is not used any form ofvalve, as the pipes at opposite ends are in permanently open connectionwith equivalent work chambers in the two motor units, without anycovering of the connection to the respective work chamber. An essentialadvantage according to the invention is that the Stirling motor has gota condensed constructional solution simultaneously as it can be achieveda particularly high efficiency with a relatively minimal volume andthereby minimal need of space and with considerable saving of materialand saving of associated equipment.

By using, according to the invention, two such motor units 85, 86 onehas according to the invention further been able to utilize thepossibility to undertake an adjustable regulation of the angularposition between the two piston arrangements. In FIGS. 8 and 9 it isshown a hydraulic coupling 98 between a shaft journal 99 in the onemotor unit and a shaft journal 100 in the other motor unit. The oneshaft journal 99 is rigidly connected with a first piston member 101 andthe other shaft journal is correspondingly rigidly connected with asecond member 102. The piston members 101, 102 are arranged in a commonchamber 103 in a common housing 104. It is shown hydraulic passages 105aand 105b, respectively, between the chamber 103 and a ring chamber 106aand 106b, respectively, and pipe connections 107a and 107b,respectively, to a three-way regulating valve 108. By means of a handle109 in the valve 108 one can by hydraulic control medium turn the pistonmembers 101 and 102 towards and from each other, as required. Preciselydefined, the piston members can be turned from the external position180° shown in FIG. 8 to the other external position via an intermediateposition (90°) which corresponds to the position as shown in FIG. 7,that is to say with 90° angular displacement between the pistonarrangements in the two motor units. From the position which is shown inFIG. 7 the piston arrangements can be turned 90° in opposite directionstowards respective two external positions. This causes that one canreduce the angular deviation from 90° towards 0° in opposite directions.In both cases the efficiency can be brought down towards zero. From theexternal position one can begin with zero efficiency and stepwiseincrease this towards a maximum by increase of the angular deviation toand beyond 90°, respectively. According to which external position thepiston members have taken in relation to each other, one can begin fromzero and continue towards maximum efficiency in respective two oppositedirections. In other words, there is the possibility to reverse thedrive direction in particularly simple manner from a stop position, asthe pivot direction is determined by the external position chosen asstarting point. Thereafter the deviation can be increased to 90° andcontinued with further increase of efficiency by increasing thedeviation beyond 90°. Consequently, there is the possibility to ensurean effective regulation of the motor power in a relatively simple andeasy manner by change of the angular deviation between the motor unitsand to reverse the pivot direction from forward operation to backwardoperation, and vice versa, according to which external position it hasbeen moved towards.

In FIGS. 10, 11 and 12 the invention is illustrated in connection with afour-stroke combustion engine 110 with a housing 10 made of two joinedhousing sections 10a and 10b. A similar arrangement can also be used inconnection with a two-stroke combustion engine.

In FIG. 10 it is indicated four combined sparking-plugs and fuel valves11a, 111b, 111c, 111d, that is to say a unity of sparking-plug and fuelvalve for its respective chamber 112a, 112b, 112c, 112d. Further, it isshown two valve controlled exhaust passages 113a and 113c and two valvecontrolled scavenge air passages 113b and 113d, each with its separatevalve 114, that is to say a passage for its respective pair of chambers.The contemporary control of sparking-plugs and fuel valves can takeplace in a manner known per se by means of known principles. Thecontemporary control of the opening and closing of the exhaust passagesand the scavenge air passages can partly take place by valve control andpartly by slide-like uncovering and covering, respectively, by means ofthe partition plate 40 and the pistons 36, respectively. The dispositionof sparking-plugs, fuel nozzles and exhaust passage outlet is localizedso in relation to the motion paths of the partition plate 40 and of thepistons 36, respectively, that the most favourably possible effect isachieved.

By a two-stroke combustion engine (not shown further) it is required tocontrol the air scavenge valve separately, while the exhaust passage canbe opened and closed only by control of the pistons and the partitionwall, respectively, or only by control of the partition wall. The airscavenging must take place by overpressure (overcharger).

The valves 114 of the respective exhaust passages and the pivot pins 42,43 of the partition wall 40 are mounted in respective cavities in themotor housing, that is to say in the joint surfaces between the housingsections 10a, 10b.

In FIG. 12 it is shown schematically the four strokes in the four-strokemotor, illustrated by four part sketches as shown by the referencenumerals 115a, 115b, 115c and 115d and which show the working steps(I-IV) for the respective four different work chambers 112a-112dlocalized between the partition wall 40 and the two valves 36.

By means of four centrally located, (imaginary) rings 116a, 116b, 116c,116d arranged concentrically in relation to each other (one for eachstroke I-IV) it is by means of openings 117a, 117b, 117c and 117d markedan open connection (in respective ring or stroke) for the four fuelvalves/sparking-plugs 11a-111d (FIG.. 10) and by means of openings 118aand 118b marked an open connection (in respective ring or stroke) forthe two exhaust valves 113a and 113c (FIG. 11) and by means of openings119a and 119b marked an open connection (in respective ring or stroke)for the two air scavenge valves 113b and 113d (FIG. 11).

It will appear from FIG. 12 that two and two of the work chambers in themotor in each part sketch (115a-115d), that is to say the two workchambers 112b, 112c and 112b, 12d, respectively, which are arrangeddiametrically opposite each other, are working in the same stroke.Further, it will appear that the two neighbour work chambers 112a, 112b,which are lying each on its side of the one piston 36 and on the sameside of the partition plate 40, have each its mutually succeedingstroke. Correspondingly, the work chambers 112c and 112d have each itsmutually succeeding stroke, that is to say corresponding stroke as thework chambers 112a and 112b, respectively. In each of the strokes I-IVas shown in the part sketches 115a-115d it is consecutively used onlytwo of the four strokes I-IV. In practice this can be solved by the useof fly wheel. Alternatively, it can be used two motor units in series,where the work chambers in the one motor unit are working with twostrokes (for example, the strokes I and II) before the strokes (forexample, the strokes II and IV) in the work chambers in the other motorunit, so that the four strokes at any time are distributed between thework chambers of the two motor units.

In a two-stroke motor the two strokes are correspondingly arranged inpairs on opposite sides of the piston and on opposite sides of thepartition plate and normally fly wheel and/or an extra motor unit arenot required. Both wih regard to the four-stroke motor and thetwo-stroke motor it can, however, be used two or more motor units on oneand the same shaft.

By to-and-fro tilting of the partition plate 40 (not shown further inFIG. 12), controlled by the rotary motion of the pistons 36 andtherefrom following forcibly to-and-fro tilting (as shown in FIG. 12),the shown work strokes I-IV (part sketches 115a-115d) for thefour-stroke motor are achieved. The beginning of the uncovering (that isto say the opening of the different inlets and outlets of the motorchambers) takes angularly place mainly as indicated by openings in theshown rings 116a-116d and angularly related to the different sketches115a-115d. It is in FIG. 12 only indicated generally by means of therings 116a-116d in which strokes the different valves etc. areactivated, without laying too much emnphasis on the positions of theseangularly in relation to each other, as the angle positions are onlyshown suggestively. Nor is it angularly suggested anything about howlarge part of the stroke (or the succeeding stroke) that is included bythe uncovering.

In stroke I it is only the fuel valvet/the sparking-plug 111a (shown atthe opening 117a) in a first chamber 112a and the fuel valve/thesparking-plug 111b (shown at the opening 117b) in the diametricallyopposite chamber 112c which are activated.

In stroke II it is the fuel valve/the sparking-plug 111c (shown at theopening 117c) and 111d (shown at the opening 117d), respectively, forthe mutually diametrically opposite chambers 112b and 112d which areactivated. In the same stroke II it is the exhaust passages 113a and113c (shown at the openings 118a, 118b) for the chambers 112a and 112cwhich are activated.

In stroke III it is the same exhaust passages 113a and 113c (theopenings 118a, 118b) which are activated for the chambers 112b and 112d.In the same stroke II it is the scavenge air passages 113b and 113d(shown at the openings 119a, 119b) which are activated for the chambers112a and 112c.

In stroke IV it is the same scavenge air passages 113b and 113d (theopenings 119a, 119b) which are activated for the chambers 112b and 112d.

From the above statement it will appear that the four fuel valves/thesparking-plugs 111a-111d are activated separately, for example byelectronic control and without control by pistons or partition plate. Inpractice the exhaust passages 113a and 113c will be open in two firststrokes and closed in two succeeeding strokes, that is to say uncoveredone by one opposite two neighbour chambers and then controlled by thepiston 36 mutually between the two neighbour chambers. Correspondingly,the scavenge air passages 113b and 113d will be open in the two firststrokes and closed in two succeeding strokes, that is to say uncoveredone by one opposite two neighbour chambers and then controlled by thepiston 36 mutually between the two neighbour chambers.

I claim:
 1. A power conversion machine comprisinga spherical housing; apiston construction mounted in said housing for rotation about a firstaxis, said piston construction including a central hub portion withpart-cylindrical surfaces and a pair of double acting pistons, eachpiston being connected on an opposite side of said hub on a second axispassing through said first axis at a common point in a center of saidhousing and being in the form of a spherical segment with oppositelydirected piston surfaces; and a partition plate pivotally mounted in andacross said housing on a third axis intersecting said common point, saidpartition plate receiving said hub portion centrally thereof and havingbearing surfaces bearing on said hub and part-cylindrical bearingsurfaces for slidably receiving said pistons.
 2. A machine as set forthin claim 1 which further comprises a crank shaft rotatably mounted onsaid first axis and passing centrally through said piston construction,a pair of rotary pins, each pin being connected at one end of said crankshaft and rotatably mounted in said housing on said first axis, andbearings mounting said pistons on said crank shaft.
 3. A machine as setforth in claim 2 wherein said crank shaft and said pins are of unitaryconstruction and said pistons and said hub portion are of two-piececonstruction.
 4. A machine as set forth in claim 1 wherein saidpartition plate has spherical end surfaces for selectively opening andclosing over inlet and outlet openings in said housing for selectivecommunication with work chambers defined on opposite sides of said plateby said pistons.
 5. A machine as set forth in claim 4 wherein saidpartition plate has a pair of pivot pins at diametrically oppositepoints rotatably mounted in said housing, said plate having a peripheralthickness tapering from adjacent end pin to a thin thickness at aperipheral point intermediately of said pins, said plate being oftwo-piece construction divided symmetrically of said hub portion.
 6. Amachine as set forth in claim 4 wherein each of said openings in saidhousing is sized to be covered and uncovered by said spherical endsurface of said plate and a spherical end surface of a respectivepiston.
 7. A machine as set forth in claim 4 which further comprises aplurality of valves, each said valve being connected to a respective oneof said openings to define a four-stroke combustion engine.
 8. A machineas set forth in claim 1 is in the form of one of a compressor, pump,pneumatic motor, hydraulic motor and steam engine.
 9. A Stirling enginecomprisinga pair of power conversion machines, each machine including aspherical housing, a piston construction in said housing including acentral hub portion and a pair of double-acting pistons connected tosaid hub on opposite sides of a common axis, each piston being in theform of a spherical segment with oppositely directed piston surfaces;and a partition plate pivotally mounted in said housing on a second axisintersecting said common axis, said plate having bearing surfacesbearing on said hub and bearing surfaces slidably receiving saidpistons; a drive shaft connected in common to said machines; an angleregulating device connecting said machines together for regulation ofthe working steps of said machines in relation to each other, saidregulating device including a pivot piston device and a regulatory valveoperatively connected to said piston device to rotate said machines inopposite pivot directions; a heating device connected to one of saidmachines; a cooling device connected to the other of said machines; anda heat exchanger about said drive shaft between said devices.